I have not forgotten about this blog, have been a bit busy with some other projects, a few details of which I’ll share.
I don’t do a lot of project development during the summer months, heck we had a decent summer in the UK this year, as I like to get out and about. I race radio control cars and boats, which is great fun. This has also given me some project ideas. I have a tripped out Tamiya Lunchbox monster truck, with up-rated motor, suspension and lights, the next step is an engine sound effects unit. I have a crude Arduino based system with a Class D amplifier that changes pitch depending on throttle. It kind of works but the sample size is limited and difficult to change, it uses Wav2c for the sample. I plan to change the design to use PCM audio files which can be handled by an Arduino. Work will continue over the winter. Not every project approach was right nor does it work first time. It was educational though.
I like my projects to use minimal components in a project, the simplicity and getting everything I can out of a Micro like the Atmega 328. It also makes it cheaper.
The other RC design, currently in the concept stage is a R/C assistant tool. The idea was borne earlier this year when I took my boat to the lake in Herne Bay, and when I got it out, nothing worked! I was 70 miles from home with limited diagnostic tools, all I had was a multimeter, not much use for a dead boat once I had verified power was present and correct. What I needed was something that could detect the presence, or lack of, the pulse width modulated signals between the modules. As well as detecting the presence of the signals, it also needs to create test signals to allow swapping in of known good sources. A microcontroller can easily do this. I would also want it to measure battery voltages to allow testing of 1-4 cell LiPo batteries. Such a device should help with most track side/pond side issues and hopefully allow for more successful days out.
The problem with my boat was due to the transmitter failing. The electrics went into Fail-safe mode. A cheap replacement radio system fixed the issue but I could not diagnose the fault until I got home.
If anyone reading this is also in to R/C and would be interested or has some suggestions, please contact me.
I originally started this blog to discuss projects in development for the Amiga retro computer, this still goes on but at a slower pace. I still manufacture the adaptors for power supplies and floppy drives for the Amiga and Atari computers and will continue for a while yet. Brexit and the poor UK exchange rates have pushed up my manufacturing costs by 25% over the last year, so I have had to increase my prices by 20%. I try to keep the costs down to be competitive but when you are only making small batches it can be difficult to get the costs low enough. I don’t make much from this endeavour, any profits are reinvested in developing new designs and financing the next production run. I do it as a service to the retro computer fraternity.
There are other ideas being progressed, the less is more approach will continue so as to avoid disappointment.
I have been asked numerous questions about the GBS8200/8220/HD9800 converter boards. I try to keep the comments moderated and I thank those who have answered some of the queries on this blog. Have you seen the great work on gbs-control project?
I have been asked about designing an improved GBS-8200 board based on the Tvia 5725. It’s a good chip, not necessarily programmed correctly, evident in the issues with motion in video games. Personally I would not use this for a video converter card of my own. These video chips are very complex. The last group of devices I used professionally took around 500 hours to develop and test a product for. You can probably see my reluctance to entertain the idea of a video converter card.
The problem with video devices, be they decoders (that convert analogue or digital video to a pixel stream) or encoders (that convert the pixel stream back to either analogue waveform or packet based/low voltage digital signal) is that the datasheets and manuals already assume you know how they work. Motion estimation, de-interlacing, chroma edge enhancement, 3D comb filters, PLL programming/coast time all have a major impact on the end video image. I should write some more on this in another post, when I get the time. Sometimes you need to play with these settings, but use the right source material to fully test them.
The TVIA5725 outputs analogue VGA by default, this was fine back in 2011 but for 2018 and beyond, any solution needs to have an HDMI output. You can convert VGA to DVI/HDMI with another adaptor but it’s much neater to do it in one or two chips and avoid extra cables.
I will try and post a bit more often, stay tuned folks.